運用拍擊干擾消除技術於功率檢測器簡化降頻架構之毫米波及太赫波光載微波無線系統

Abstract

自從高資料速率無線應用的需求成長，載波頻率就必須被增加來提供足夠的頻寬。因此，V-band (57-64 GHz)、W-band (75-110 GHz)甚至到THz (100-2000GHz)因為擁有巨大的頻寬而吸引了許多注意。然而隨著載波頻率的增加，訊號的頻寬以及本地震盪器的功率問題對於使用混頻器降頻的系統將會在元件設計上變成了一個挑戰。於本論文中使用功率偵測器的降頻架構因此被使用來簡化基地台端。然而伴隨著降頻產生的訊號對訊號拍擊干擾將會變成帶內干擾影響被降頻的訊號品質，所以訊號對訊號拍擊干擾消除法將會被用來消除訊號對訊號拍擊干擾。在提出的V-band光載微波無線系統中馬氏調變器將會被用來進行光訊號的產生。因此經由4公里光纖以及3公尺無線傳輸的資料速率為28.8-Gbps V-band光載微波無線訊號能夠在前向錯誤更正限制下被達成。更甚的是，多天線輸入多天線輸出技術及子載波多工技術將會被使用來改善頻譜效益。 在毫米波以及THz波的無線傳輸中，高複雜度及高成本的射頻訊號的產生程為了一個巨大的挑戰。因此於光載微波無線系統利用電致吸收調變雷射來進行光訊號產生能夠降低中央控制台的複雜度，而且額外的雷射將會被加入來與產生的光訊號結合以用來在低複雜度下產生射頻訊號。而後射頻訊號將會利用功率檢測器進行降頻。因此簡化的中央控制台以及基地台將會在提出的光載微波無線系統中被達成。最後經由25公里光纖以及3公尺無線傳輸的資料速率為10.5-Gbps V-band光載微波無線訊號能夠在前向錯誤更正限制下被達成。

Since the demand on high data-rate wireless applications are growing, the carrier frequency needs to be increased for offering the enough bandwidth. Therefore, the V-band (57-64GHz), W-band (75-110 GHz) and even THz (100-2000 GHz) have attracted attention due to the huge bandwidth. However, as the carrier frequency increases, the signal bandwidth and local oscillator (LO) power in mixer-based down-conversion will become a challenge due to the component design. In this thesis, the down-conversion using power detector is employed to simplify the base station (BS). Nevertheless, the accompanied signal-to-signal beating interference (SSBI) will become in-band to interfere the down-converted signal, so the SSBI mitigation is utilized to eliminate the SSBI. In the proposed V-band RoF system, the mach-zehnder modulator (MZM) is employed to generate optical signal. Hence, the 28.8-Gbps V-band radio-over-fiber (RoF) signal over 4-km fiber and 3-m wireless transmission is achieved under the FEC limit. Moreover, the multiple-input multiple-output (MIMO) technology and subcarrier multiplexing (SCM) technology will be used to improve spectral efficiency. In the MMW and THz wave wireless transmission, the high complexity and high cost of RF signal generation will become a great challenge. Hence, employing electroabsorption modulated laser (EML) for optical signal generation in RoF system, the complexity of central station (CS) can be reduced, and the additional laser is added to combine with optical signal for generating RF signal. Then, the RF signal is down-converted by power detector. Therefore, the simplified CS and BS will be accomplished in proposed RoF system. Finally, 10.5-Gbps V-band RoF signal over 25-km fiber and 3-m wireless transmission is achieved under the FEC limit.